1. Field of the Invention
The present invention relates generally to heat exchangers, and more particularly to a method and apparatus for constructing heat exchanger tanks that allows for flexibility in size and geometry.
2. Description of the Related Art
A variety of heat exchangers may be used in the cooling system of an internal combustion engine of a motor vehicle. The cooling system disclosed in U.S. Pat. No. 5,570,738 to Christensen includes three different heat exchangers disposed in series flow relationship with one another: (1) a condenser for receiving high pressure, superheated refrigerant gas from the refrigerant compressor and condensing the gas into a high pressure liquid for expansion and cooling of the vehicle cab; (2) a charge air cooler (CAC) for cooling the turbocharged engine intake air before the air enters the engine for the combustion process; and (3) a radiator for eliminating waste heat from the internal combustion engine of the vehicle.
Heat exchangers typically include a central core, and generally vertically disposed end manifolds or header tanks attached to opposite lateral ends of the core. The core comprises a plurality of tubes and fins, typically disposed in alternating laterally extending rows, with the tubes communicating with header tanks so as to provide a flowpath through the heat exchanger. Ambient cooling air is forced across the tubes and fins during operation of the vehicle resulting in heat transfer from the gas or fluid flowing through the heat exchanger to the ambient air stream.
Heat exchangers, such as the radiator, CAC and condenser are surface area dependent, in that the temperature reduction achievable in a heat exchanger depends on the available surface area of the design. Therefore, a myriad of different size heat exchangers are necessary to accommodate the different thermal requirements present in different applications. Varying the size of a heat exchanger requires varying the size of the header tanks. However, conventional heat exchanger tank designs require specific tooling for each different design application, as the header tanks are generally cast as a single piece. This is expensive and results in long lead times for both prototype and production parts.
Consequently, a need exists for an improved heat exchanger tank design and for a method of constructing heat exchanger tanks that allows for flexibility in size and geometry.
The present invention, therefore, provides a method for construction of heat exchanger header tanks that allows for flexibility in size and geometry. The header tanks are constructed from a set of basic components that can be assembled as required to match a desired tank design for any application. The basic components are cast or formed from simple sheet metal parts. The components are assembled to produce a tank of the desired size and geometry. The individual components are then connected together, and the final tank assembly is then affixed to the heat exchanger core.
The basic components of the heat exchanger tanks consist of castings which form the tank ends, inlet/outlet fittings, and combination tank ends with inlet/outlet fittings and structural support attachments, and formed sheet metal center sections which connect the cast portions to form the completed tank.